Iterative MMSE Detection and Interference Cancellation for Uplink SC-FDMA MIMO Using HARQ

For high-speed packet access, hybrid automatic repeat request (HARQ) and multiple-input multiple-output (MIMO) multiplexing are indispensable techniques. As the multiple-access technique, single carrier (SC)-frequency-division multiple-access (FDMA) using transmit filtering is promising. The use of square root Nyquist transmit filter reduces peak-to-average power ratio (PAPR) of the transmit SC-FDMA signal and increases the frequency diversity gain. However, if the carrier-frequency separation among multiple-access users is kept the same as in the case of the transmit filter´s roll-off factor α=0 (i.e., brick wall filter), the adjacent users´ signal spectra overlap and the multi-user interference (MUI) is produced. In this paper, we propose an iterative minimum mean square error signal detection and interference cancellation (MMSED-IC) for turbo coded uplink SC FDMA MIMO using HARQ. In the proposed MMSED-IC, not only the inter-antenna interference (IAI) and residual inter-symbol interference (ISI) but also MUI are cancelled in an iterative fashion. We evaluate the HARQ throughput performances by computer simulation, and show that the use of roll-off factor α=1 achieves the highest throughput performance.